The long-term goal of the proposed research is to determine whether precursors of hypertensive disease are present in infancy. In this project, we wish to determine whether blacks, who are more likely to develop hypertensive disease, exhibit cardiovascular characteristics at birth, which differ from those of white newborns, and which may be related to subsequent pathogenesis of hypertensive disease. In particular, we will assess the degree to which heart rate and systolic blood pressure in the newborn vary as a function of race and also of socioeconomic class. The finding of higher heart rate during quiet sleep in black newborns as compared to white newborns of lower socioeconomic, urban families was replicated. In a new sample of full-term, appropriate weight newborns, including 61 black newborns and 71 white newborns, heart rate was 8 beats per minute faster in the black newborns (p less than .001). No significant difference was found in systolic blood pressure in 67 black newborns compared to 74 white newborns. Heart rate did not correlate significantly with systolic blood pressure. Bibliographic references: Schachter, J., Kerr, J. L., Wimberly, F.C. & Lachin, J.M. Heart rate levels of black and white newborns. Psychosom. Med., 1974, 36, 513-524.